Pouch type lithium secondary battery

Abstract

A pouch type lithium secondary battery includes: an electrode assembly including electrode tabs respectively connected to two electrodes, the two electrodes having different polarities; and a case to house the electrode assembly such that the electrode tabs extend to the outside of the case, wherein one stepped part through which the two electrode tabs simultaneously extend is formed in a sealing portion of the case. In the electrode sealing portion of the pouch type lithium secondary battery having short width, sealing of the case is improved by the one stepped part, thereby improving efficiency of the manufacturing process of the battery.

What is claimed is: 
     
       1. A pouch type lithium secondary battery, comprising:
 an electrode assembly including two electrodes with different polarities and two electrode tabs respectively connected to the two electrodes; 
 a case comprising a first case piece and a second case in combination to house the electrode assembly, the first case including a first surface and the second case configured to cover the first surface; and 
 a sealing part interposed between the first case and the second case along the first surface, wherein the two electrode tabs extend through one stepped part formed in the sealing part, wherein the one stepped is raised above the first surface, 
 wherein the width of the one stepped part is wider than the width of the outside ends of the two electrode tabs, and 
 wherein the whole thickness of the stepped part is substantially uniform. 
 
     
     
       2. The pouch type lithium secondary battery of the  claim 1 , wherein the two electrode tabs are respectively surrounded by insulating members, and wherein the stepped part comprises two side parts and one center part between the two side parts, wherein the two side parts include the first case, the second case and the insulating member, wherein the center part includes the first case, the second case, the insulating member and the two electrode tabs, and wherein the thickness of the two side parts is larger than a thickness of the first case and the second case. 
     
     
       3. The pouch type lithium secondary battery of  claim 2 , wherein a width of the center part is smaller than a width of the outside ends of the insulating members along the sealing part.